1. Field of the Invention
The present invention pertains to the art of refrigerators and, more particularly, to a sensor system employed in a dispenser mounted in a refrigerator door.
2. Description of the Related Art
Refrigerators having built-in ice/water dispensers are well known in the art. In general, the dispensers are mounted to a door of the refrigerator for the purpose of dispensing ice and/or water without requiring a user to access a refrigerator compartment. A typical dispenser includes a dispenser well into which a container is placed. Once the container is in position, an actuator is operated to release the ice and/or water into the container.
In many cases, the actuator is a pressure sensitive mechanical switch. Typically, the switch is operated by pushing the container against, for example, a lever. The lever, in turn, operates the switch that causes the ice and/or water to be dispensed. A number of dispensers employ multiple actuators, one for ice and another for water, while other dispensers employ a single actuator. Dispensers which employ a single actuator typically require additional control elements that enable a user to select between ice and water dispensing operations. Several manufacturers have converted from mechanical switches to electrical or membrane switches. Functioning in a similar manner, a container is pushed against the membrane switch to initiate the dispensing operation. Still other arrangements employ actuator buttons provided on a control panel of the dispenser. With this arrangement, the user continuously depresses a button to release ice and/or water into the container. In yet another arrangement, sensors are mounted in the dispenser well and function to sense a presence and size of the container. The dispenser automatically begins dispensing ice or water based on the presence of the container and stops dispensing before the container overfills. In this case, the level of liquid or ice dispensed is dependent on the container, and cannot be altered by a consumer based on the amount of liquid or ice desired.
Over time, mechanical and membrane switches wear out. Physical interaction with the switches results in wear and tear on contact points, springs, levers and the like, which eventually require replacement. Another drawback with existing systems is the lack of an automatic cut-off feature. More specifically, once activated, the dispenser will discharge water or ice until the pressure is removed from the actuator. If the user is momentarily distracted or if the dispenser is operated by an inexperienced individual such as a child, the level of ice or water can overflow the container.
There also exist drawbacks with the systems that employ automatic actuators. Most active sensors cannot differentiate between a container and a child's hand. Thus, in such systems, the mere act of a child inserting a hand or other object into the dispenser well will initiate a dispensing operation. In addition, active sensors require both the sending and receiving of signals. Sensors of this type may require periodic alignment and necessitate the use of multiple components which further add to the overall cost and complexity of the appliance.
Therefore, despite the existence of refrigerator dispensers in the prior art, there still exists a need for an enhanced refrigerator dispensing system. More specifically, there exists a need for a refrigerator dispensing system that can be utilized regardless of the shape or size of the container to be filled, and that allows for a hands-free dispensing event.